Monolayer, non-differentiated tracheo-bronchial epithelial cell cultures have been helpful in furthering the understanding of diseases such as cystic fibrosis and asthma, characterizing viral infection in the airway epithelia, and advancing our knowledge of tracheal and bronchial inflammation. In addition, such cultures have enabled and/or facilitated inhalation toxicology studies and allowed insight into neoplastic progression in the airways. Differentiated, stratified cultures which adopt an in vivo-like phenotype are anticipated to add further to these advances. Nonetheless, a differentiated, commercially available model of the airway epithelia does not exist. Phase I research will investigate the feasibility of producing a tissue culture model of the airway epithelia which mimics its in vivo progenitors in structure and function. Normal, human derived, tracheobronchial epithelial cells will be expanded in monolayer culture, cryopreserved, and then used to produce stratified, differentiated tissue cultures. Experiments will investigate a variety of culture parameters and cultures will be characterized using microscopic and immunospecific techniques. Finally, the technical and commercial viability of the model will be assessed. PROPOSED COMMERCIAL APPLICATIONS: The differentiated, tissue culture model here proposed would facilitate the screening and testing of new pharmacologic agents and therapies to combat the various diseases and disorders affecting the airway epithelia. In addition, an organotypic tissue model would be useful for toxicology, cancer, and drug deliver studies.